If it costs 3n+5, you have to plug 7 in for n and solve. 3(7)+5=26 so $26
If an hour passes the bacteria would have tripled so 80 times 2 is 160.
If 2 hours pass the bacteria population would be 80 times 4 is 320.
I hope this helped you hon :)
Answer:
the answer is D The results of all previous events do not affect the probability of future events.